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The sodium dual ion battery (Na‐DIB) technology is proposed as highly promising alternative over lithium‐ion batteries for the stationary electrochemical energy‐storage devices. However, the sluggish reaction kinetics of anode materials seriously impedes their practical implementation. Herein, a Na‐DIB based on TiSe2‐graphite is reported. The high diffusion coefficient of Na‐ions (3.21×10−11–1.20×10−9 cm2 s−1) and the very low Na‐ion diffusion barrier (0.50 eV) lead to very fast electrode kinetics, alike in conventional surface capacitive storage systems. In‐situ investigations reveal that the fast Na‐ion diffusion involves four insertion stage compositions. A prototype cell shows a reversible capacity of 81.8 mAh g−1 at current density of 100 mA g−1, excellent stability with 83.52 % capacity retention over 200 cycles and excellent rate performance, suggesting its potential for next‐generation large scale high‐performance stationary energy storage systems. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) metallic transition-metal dichalcogenides (TMDCs), such as 1 T-TiSe2, have recently emerged as unique platforms for exploring their exciting properties of superconductivity and the charge density wave (CDW). 2D 1 T-TiSe2 undergoes rapid oxidation under ambient conditions, significantly affecting its CDW phase-transition behavior. We comprehensively investigate the oxidation process of 2D TiSe2 by tracking the evolution of the chemical composition and atomic structure with various microscopic and spectroscopic techniques and reveal its unique selenium-assisting oxidation mechanism. Our findings facilitate a better understanding of the chemistry of ultrathin TMDCs crystals, introduce an effective method to passivate their surfaces with capping layers, and thus open a way to further explore the functionality of these materials toward devices. [ABSTRACT FROM AUTHOR]